9 ps light i ao
TRANSCRIPT
![Page 1: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/1.jpg)
9 Physical Sciences
Light I
![Page 2: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/2.jpg)
Note
Important Points
![Page 3: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/3.jpg)
Light is a form of electromagnetic (EM) radiation energy that travels in transverse waves or straight lines.
What is light?
![Page 4: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/4.jpg)
Light travels faster than sound at a speed of 300, 000, 000 m/s.
c = 300, 000, 000 m/s.
Speed of Light
![Page 5: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/5.jpg)
Light travels faster than sound.During a thunderstorm, you will notice that lightning strikes first.This is then followed by thunder.
![Page 6: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/6.jpg)
Light travels in straight lines. To demonstrate this property, just close your eyes. Did you realise that you could not see any light?
Properties of Light
![Page 7: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/7.jpg)
There are seven different types of EM waves.
Properties of Light
![Page 8: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/8.jpg)
low frequency
Increasing frequency
high frequencylong wavelength short wavelength
Properties of Light
![Page 9: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/9.jpg)
Each form of light travels at the same speed in a vacuum.
![Page 10: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/10.jpg)
Properties of Light
![Page 11: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/11.jpg)
Artificial sourceNatural source Sources of Light
![Page 12: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/12.jpg)
Smooth surfaces like the calm water allows light to be reflected evenly.
This is known as a specular reflection.
Smooth Surfaces
![Page 13: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/13.jpg)
Rough surfaces like the rippled and paddled water allows light to be reflected unevenly.
This is known as a diffuse reflection.
Rough Surfaces
![Page 14: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/14.jpg)
Objects that emits (or produces) their own light.
Luminous Objects
![Page 15: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/15.jpg)
Objects that reflects light.Do not emit any light.
Non-luminous objects
![Page 16: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/16.jpg)
How do we see things?
![Page 17: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/17.jpg)
Light is emitted from luminous objects.
Light hits an object and bounces off.
Our eyes receives the light and is focused on the retina.
Why can we see things?
![Page 18: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/18.jpg)
Visible light is composed of 7 colours of different wavelengths and frequencies.
Why are objects coloured?
![Page 19: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/19.jpg)
When light hits the banana, all colours except for yellow will be absorbed.
Why are objects coloured?
![Page 20: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/20.jpg)
The colour yellow will be reflected and received by the retina in the eye to be interpreted.
Why are objects coloured?
![Page 21: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/21.jpg)
Objects that allow all light to go through.
Transparent Objects
![Page 22: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/22.jpg)
Objects that allows some light to pass through.
Translucent Objects
![Page 23: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/23.jpg)
Objects that do not allow light to pass through.
Opaque Objects
![Page 24: 9 PS Light I AO](https://reader034.vdocuments.us/reader034/viewer/2022042722/589e44191a28ab07478b6e3b/html5/thumbnails/24.jpg)
Transparent• Glass
Translucent• Ice
Opaque• Straw• Cutlery
Example: A Glass of Coke